Applied Nonlinear Compressor Control with Gain Scheduling and State Estimation

Abstract

Subsea gas compressors are key components for both increased and accelerated hydrocarbon production. Compressors enable the development of fields that are remote, in deep waters, or have low and/or reduced reservoir pressure. In this paper, we present a gain scheduling controller for a nonlinear centrifugal compressor model, coupled with an extended Kalman filter estimating an unmeasured system state. The controller is designed for the normal operating region of a GT2252 turbocharger compressor section, planned for future small-scale experiments. The controller is developed with pole placement design on the equivalent linearized dynamics of the nonlinear model in a set of operating points. The linearized closed-loop system in each operating point is then provably locally asymptotically stable. The controller and estimator are analyzed in simulations, and show to achieve tracking of the desired plenum pressure using the estimate of the compressor mass flow.